Tatsuya is really talented but also a bit of a slacker. Since middle school, Kazuya has received awards and recognition for excellence as a pitcher and baseball player. Tatsuya, however, is more inclined to let his brother take the limelight, as he is unwilling to directly compete with Kazuya. This includes Minami as well; while most people (including their parents) suggest that Minami and Kazuya will make a perfect couple, Minami tends to prefer Tatsuya.
A story of growing up, letting go, falling in love, and falling out. It follows the relationships of Sana, Hayama, and friends.
One Diclonius girl, Lucy, breaks out of confinement, kills her guards and escapes. She falls into the ocean after being shot and ends up on a beach. There, she meets Kota and Yuka. They name her Nyu and begin to live with her.